1. Field of the Invention
The invention relates to electrical switches, particularly those switches used in computer keyboard applications.
2. Prior Art
In the computing industry, it is quite common to enter data into a computer by means of a keyboard. Typically, the keyboard is comprised of a plurality of discrete switch assemblies coupled to a printed circuit board having circuit pathways or contacts thereon. Upon depressing or activating a switch disposed on the keyboard, an electrical contact is achieved and appropriate data is thereby entered by the user.
As a result of the heavy and continuous demand placed on keyboard switches by frequent use, switch assemblies of this type must be highly reliable and yet cost effective. Numerous attempts to achieve a low cost but reliable keyboard switch have been made in recent years. For example, one common type of switch assembly provides electrical contacts spaced apart on the base of the switch housing. Upon depressing the key, an actuator incorporating a circular conductive pad disposed within the central portion of the structure of the actuator is forced downward and across the electrical contacts, thereby achieving an electrical connection. The use of a conductive pad disposed within the actuator requires that a shunt across at least two separate and distinct electrical contacts must occur in order to activate the switch. However, switches of this type do not achieve the desired level of reliability since by depressing the key off-center, it is possible that the circular conductive pad may not physically contact each spaced apart contact and thereby fail to provide an electrical coupling.
In addition, switches which incorporate an actuator of the type described above do not provide sufficient tactile sensation to alert the user when electrical contact occurs. Thus, both speed and efficiency are typically sacraficed when using keyboard switches known in the prior art, inasmuch as the user must fully depress each switch in order to be certain that proper electrical contact has been achieved.
As will be disclosed below, the present invention provides a simple but highly reliable and cost effective keyboard switch assembly which overcomes the inherent disadvantages of the prior art devices.